Ozone ups and downs

15 November 2017

Climate scientists studying three decades of ozone measurements from seven satellites see a positive trend in global recovery thanks to international efforts to curb ozone-depleting substances.

The part of Earth's atmosphere with high concentrations of ozone gas protects life on Earth from the Sun's ultraviolet radiation. However, pollutants can break down ozone, thinning this ozone layer and creating the infamous ozone hole.

The depletion of ozone in our atmosphere and subsequent increase in ultraviolet exposure causes skin cancer, cataracts and immune system damage in humans, and injures animals, plants and even microscopic phytoplankton.

Starting in the 1970s, ozone in the stratosphere – some 11–50 km above Earth's surface – began to decline worldwide. The largest drop was in the upper stratosphere, at 4–8% per decade.

The trend was interrupted following international agreements on the reduction of ozone-depleting substances and the first signs of ozone recovery were seen by satellites.